In spectroanalytical systems using emission sources, material to be analyzed is introduced into an analytical region and excited to spectroemissive levels sufficient to emit detectable radiation characteristic of elements in the sample. The resulting emitted radiation typically is dispersed and analyzed spectroscopically to quantitatively determine elemental compositions of sample materials. An example of such analyses is the contract lab program (CLP) in which sample materials are analyzed for the toxic elements, arsenic, thallium, selenium and lead. Prior analytical systems for measurements of this CLP type have employed an atomic absorption graphite furnace with a hollow cathode lamp for each element of interest. An object of the invention is to provide a polychromator with improved detection limits suitable for analyses of the CLP type.